Especially JCE: July 2016

Back to school time means back to lab time too. Students new to chemistry have a lot on their plates the first few labs—learning unfamiliar safety procedures, becoming accustomed to writing lab reports, even figuring out which glassware they’re looking for in their lab space. How can teachers help them to navigate this newness? Two articles in the July 2016 issue of the Journal of Chemical Education are useful resources for “back to lab” time.

Familiarity with Lab Equipment

Could your students pick an Erlenmeyer flask out of a glassware lineup? What about a watch glass? A drawerful of equipment that we find familiar can be a confusing jumble to others. Kavak and Yamak’s JCE article (available to JCE subscribers) starts with some of the most common glassware and lab equipment and turns their identification into a game with visual and text components. Students split into two teams, then take turns reading aloud definitions and functions of a piece of equipment from a card drawn from the game pile. An opposing team member attempts to identify the equipment’s name, but must also find its picture on the gameboard (see figure).

Instead of the gameboard, which would need to be projected or shared in a central location for teams to see, you could have an actual collection of your lab equipment at a table. You can also customize which cards to include in the game—if you don’t use separatory funnels, don’t use that card. The cards and gameboard are available to subscribers in the article’s online supporting information as a pdf. There are some spelling errors in the cards, plus a picture of the gameboard is used as a graphic behind the facts about each piece, making the text harder to read. The game was tested with chemistry pre-service teachers, who provided analysis of its strengths and weaknesses, along with possible extensions. I agree with the suggestion that it could be turned into an electronic version as well, for individual use.

For another resource, I appreciated Compound Interest’s post and downloadable infographic from last year: . They are not all items you’d find in an introductory lab, but it’s an easy reference to a lot of common pieces.

A Meaningful Lab—No Experience Necessary!

Erdmann and March’s  (available to JCE subscribers) fills the common requirements of an early lab: students practice sample handling, collect and record data, and write up the lab. After learning a bit about pH, students are asked to predict how the pH of three ammonia concentrations (0.00625 M, 0.0125 M, and 1.0 M) would trend. Would pH increase or decrease with increasing concentration? The main technique is to qualitatively measure pH of ammonia samples using paper pH strips. 

If that's where it ended, this would just be a typical lab. The authors add a twist: students are informed that not all of the sample containers are properly labeled. This, along with the somewhat subjective nature of determining the color of a pH strip for samples that are close in pH, provides ample fodder for discussion within lab groups and for discussion as a class. Individual students test each sample three times, then work with their group to agree on a single pH value for each sample to report to the class. After all groups report, each is then given an unknown. After testing of the unknowns and reporting each group’s agreed-upon value again, a class discussion is held. The authors offer descriptions of likely discussion topics in the figure labeled “Box 1” in the article. Can students analyze patterns in the reported data to determine which samples are likely mislabeled? Did any students feel pressured to change their results so they matched the rest of their group?  What are the ethics associated with lab notebooks? What happens if a student forgot to record the code from his or her sample—is the experiment reproducible?

The article also has supporting information online. It includes a student handout, a table for mislabeling solutions, and an in-class assignment handout with rubric. There are both pdf and Word versions, if the instructor wishes to edit the wording to fit his or her situation.

Look for more resources in Mary Saecker’s post

What Do You Use?

What do you use in your classroom during your first labs? Please share in the comments below, or in a separate post. Contributors can submit an article or share a "Pick" of another JCE article or other published resource. Submit a . Questions? Contact us using the XChange’s .

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